The heroes bring their Circus of Wayward Wonders to the city of Escadar to capitalize on their newfound fame and skills. But old enemies lurk in the city, including the cruel Mistress Dusklight and her Celestial Menagerie. Investigating the looming xulgath threat in a shuttered temple to Aroden, the dead god of humanity, the heroes learn that all their foes are working together. The revelation forces them to enter the Celestial Menagerie to bring the evil ringmaster to justice.

Legacy of the Lost God is a Pathfinder adventure for four 5th-level characters. This adventure continues the Extinction Curse Adventure Path, a six-part, monthly campaign in which the heroes lead a traveling circus as they unravel a plot to eradicate all life from the islands of the Inner Sea. This adventure also includes information about catfolk of Golarion and the villainous xulgaths, as well as new monsters and circus-themed rules.

Each monthly full-color softcover Pathfinder Adventure Path volume contains an in-depth adventure scenario, stats for several new monsters, and support articles meant to give Game Masters additional material to expand their campaign. Pathfinder Adventure Path volumes use the Open Game License and work with both the Pathfinder RPG and the world's oldest fantasy RPG.